<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="container">
    <div class="item item1"></div>
    <div class="item item2"></div>
    <div class="item item3"></div>
    <div class="item item4"></div>
    <div class="item item5"></div>
    <div class="item item6"></div>
    <div class="item item7"></div>
    <div class="item item8"></div>
    <div class="item item9"></div>
    <div class="item item10"></div>
    <div class="item item11"></div>
    <div class="item item12"></div>
    <div class="item item13"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
    <div class="item item14"></div>
  </div>
</body>

<style>
  #container {
    display: grid;
    grid-template-columns: 200px 200px 200px 200px;
    grid-template-rows: 200px 200px 200px 200px;
    gap: 10px;
    width: 1000px;
    height: 1000px;
    border: 1px solid red;
  }

  .item {
    /* width: 200px;
    height: 200px; */
    background-color: aquamarine;
  }
</style>

</html>